Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• Cs2CO3 as shown in Scheme 1. The substrate scope exhibits that on using electron-deficient diaryliodonium salts as an arylating agent, α-fluoroacetamides 8 were obtained in moderate to good yields through a spontaneous arylation/deacylation cascade. The deacylation reaction is considered due to the

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• in case of compound E-β-46b, the signaling cascade was investigated also for derivative E-β-46e. Important biochemical steps were again activation of caspase-3, downregulation of XIAP, upregulation of p53 and TRAIL receptor 2, STAT-3 dephosphorylation, and loss of mitochondrial membrane potential

• viability and in induction of apoptosis [50]. The presence of this compound results in downregulation of the caspase antagonistic proteins c-FLIP and XIAP via caspase-8 and caspase-3 in the (extrinsic) apoptosis cascade. Similarly as discussed above for the activity of 3-alkylideneoxindole-N-glycosides

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• synthesis of E-o-hydroxystilbenes, albeit via a cascade hydrolyzation–decarboxylation reaction at a very high temperature (Figure 2c) [18]. However, a metal-free decarbonylation–oxidation method for benzofuranones is still unprecedented. The earlier report [2] on the Ni-catalyzed decarbonylation–oxidation

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

• Andrey N. Komogortsev,
• Constantine V. Milyutin and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• of dicyclopentadiene (DCPD) in a continuous flow microreactor [15]. Where cyclopentadiene was the target intermediate formed by the thermal dissociation of dicyclopentadiene, cascade oligomerization was a side reaction to be avoided. Based on the deep understanding of the kinetic differences between

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• ]-rearrangement of ene-aldimines 149, catalysed by the BINOL-derived chiral phosphoric acid (CPA) (R)-151 (Scheme 31) [46]. DFT computational analysis suggested that the reaction proceeds via a complex cascade that involves the fragmentation of ene-aldimine 149 to form an imine methylene cation, which in turn

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

• [107] (Figure 11B). Werth and Sigman [127] investigated multiple nucleophilic additions to nitroalkenes, catalysed by bifunctional hydrogen bond donors, observing good correlations to new bi-functional donors, new nucleophiles, new electrophiles and even similar cascade-type reactions. In the authors

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• (R = EWG-C6H4, E = PhS and PhTe) in moderate to high yields [30]. Very few examples of intermolecular cascade reactions with imidoyl radicals as key intermediates have been reported. The intermolecular cascade reaction of diselenide, electron-deficient acetylene, and isocyanide under photoirradiation

• quinoxaline synthesis was reported to proceed by irradiation with visible light in the presence of dibenzylamine ((PhCH2)2NH, MeCN, rt, blue LED) [64]. This reaction involves a visible-light-induced single electron transfer (SET) process. An efficient radical cascade cyclization has also been reported, in

From perfluoroalkyl aryl sulfoxides to ortho thioethers

• Yang Li,
• Guillaume Dagousset,
• Emmanuel Magnier and
• Bruce Pégot

Beilstein J. Org. Chem. 2024, 20, 2108–2113, doi:10.3762/bjoc.20.181

• study, many research groups described a strategy for ortho-C–H functionalization of aryl sulfoxides with various nucleophiles via a cascade reaction of interrupted Pummerer reaction/sigmatropic rearrangement (Scheme 1a) [6][7][8][9][10][11]. A large range of nucleophiles, such as phenols [12][13][14][15

Diastereoselective synthesis of highly substituted cyclohexanones and tetrahydrochromene-4-ones via conjugate addition of curcumins to arylidenemalonates

• Deepa Nair,
• Abhishek Tiwari,
• Banamali Laha and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2024, 20, 2016–2023, doi:10.3762/bjoc.20.177

• Deepa Nair Abhishek Tiwari Banamali Laha Irishi N. N. Namboothiri Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400 076, India 10.3762/bjoc.20.177 Abstract A cascade inter–intramolecular double Michael strategy for the synthesis of highly functionalized cyclohexanones

• treatment of Alzheimer's disease [3][4]. Likewise, RL91 and BHMPC are active for selective cell growth inhibition of the resistant lines (Figure 1) [5][6]. Their synthesis mainly involves a cascade Michael–aldol reaction between enones and suitable Michael donors such as β-ketosulfones, β-diketones, or

• starting materials for cascade/domino reactions. Curcumin is the key component present in turmeric and is responsible for its various biological activities. Turmeric has been used in many forms for potential health benefits and as a traditional spice for centuries [11]. Curcumin exhibits diverse biological

Solvent-dependent chemoselective synthesis of different isoquinolinones mediated by the hypervalent iodine(III) reagent PISA

• Ze-Nan Hu,
• Yan-Hui Wang,
• Jia-Bing Wu,
• Ze Chen,
• Dou Hong and
• Chi Zhang

Beilstein J. Org. Chem. 2024, 20, 1914–1921, doi:10.3762/bjoc.20.167

• –intramolecular cyclization cascade with excellent chemoselectivity in aqueous CH3CN [25]. Herein, as part of our continuing studies of heterocyclic scaffold synthesis mediated by hypervalent iodine reagents, we present the solvent-dependent chemoselective synthesis of a series of isoquinolinones mediated by PISA

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• approach offers several advantages since multiple bond formation, synthetic transformation and heterocyclic construction can be conducted in a single reactor [56]. Novel scaffolds derived from the GBB products have been successfully constructed through three types of one-pot synthesis, namely cascade

• /domino reaction, one-pot stepwise synthesis and multicomponent reaction. In the one-pot cascade reaction, the complexity of heterocycles was achieved due to the presence of functional groups formed in the GBB reaction which allow further reactions to occur. In the case of one-pot stepwise synthesis, the

• Ganesher [57] reported the one-pot cascade synthesis of indole-imidazo[1,2,a]pyridine hybrids 61 (Scheme 23). In this study, the convertible isocyanide 1-isocyano-2-(2,2-dimethoxyethyl)benzene (59, Kobayashi–Wessjohann isocyanide) was utilized as one of the precursors in the GBB reaction. The acetal

Ugi bisamides based on pyrrolyl-β-chlorovinylaldehyde and their unusual transformations

• Alexander V. Tsygankov,
• Vladyslav O. Vereshchak,
• Tetiana O. Savluk,
• Serhiy M. Desenko,
• Valeriia V. Ananieva,
• Oleksandr V. Buravov,
• Yana I. Sakhno,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2024, 20, 1773–1784, doi:10.3762/bjoc.20.156

• of Ugi bisamides based on pyrrole-containing β-chlorovinylaldehyde and convertible isocyanides. The subsequent post-transformation of the products by acidic hydrolysis conditions should then lead to an acidic component. However, due to the cascade nature of the multicomponent processes and the

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• reported the formation of an α,α-dicyanoalkene from dehydroepiandrosterone (DHEA) and its efficient transformation to dienamides 15 in a single step via a cascade reaction [15][16]. The construction of the β-lactam ring involved a cascade 4-endo N-cyclization/aerobic oxidation sequence in presence of

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• pathways are described with a focus on the biosynthetic intermediates and enzymatic transformations that enable cascade reactions and pinpoint modifications. This focus highlights how these biosynthetic pathways are applicable to the development of streamlined chemo-enzymatic synthesis processes. The

• (Scheme 7 and Scheme 8) [68]. This chemo-enzymatic total synthesis represents a pioneering approach, as it ingeniously integrates biosynthetic intermediate mimics, synthesized through multiple steps, into the biosynthetic pathway. A cascade of stereoselective carbon chain elongation and regioselective

• JuvEV, homologous enzymes to TylGIV and TylGV (Scheme 8) [68]. Reconstruction of the JuvEIV–JuvEV-catalyzed cascade enzymatic conversions successfully furnished 4 in one pot from chemically synthesized thioester 77 mimicking biosynthetic intermediate 64. For the chemical synthesis of mimic 77, the left

Synthesis of substituted triazole–pyrazole hybrids using triazenylpyrazole precursors

• Simone Gräßle,
• Laura Holzhauer,
• Nicolai Wippert,
• Olaf Fuhr,
• Martin Nieger,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2024, 20, 1396–1404, doi:10.3762/bjoc.20.121

• accessed from the respective amines or organohalides (5 and 6, Scheme 1) [14][16][17][18]. Few examples of triazole–pyrazole hybrids, such as 13, have also been synthesized through a modified Sakai reaction [19], a reaction cascade involving the elimination of an azole [20] or in the n-butyllithium

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• intramolecular Cannizzaro reaction while accomplishing the synthesis of the bicyclic core structure of proposed ottelione A (47) [85]. Commencing from the Diels–Alder adduct 48, an enzymatic desymmetrization of the reduced diol 49 formed the enantiopure 50 (ee >99%). A cascade of reaction sequences delivered the

• scaffolds Burroughs et al. developed an intramolecular Cannizzaro-based cascade synthesis for the construction of 8-membered cycloocta-2,5-dienones [91]. The initial formation of the organolithium species 82 formed by acetylide addition to the ortho-substituted bromoaldehyde 81, was subjected to halogen

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• bisepoxyisoindole-7-carboxylic acids were obtained in good yields after a practical isolation procedure. The results obtained in this study demonstrate the potential of vegetable oils and their renewable materials to provide a reaction medium that is more sustainable than conventional organic solvents in cascade

• ][98]. Therefore, in the present study, we report for the first time a milder, greener strategy to prepare a series of epoxyisoindolinones from aminofuranes and maleic anhydride via cascade amidation and stereocontrolled IMDAF reaction in bio-based solvents as an alternative reaction medium. Results

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• of the substituent located at carbon C3 of the chromone moiety and also on the type of nucleophile employed. Keywords: cyclizations; 1,3-dicarbonyl compounds; domino reactions; heterocycles; regioselectivity; silyl enol ethers; Introduction Domino reactions (also called cascade or tandem reactions

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• the stable CM• radical through electron paramagnetic resonance. Based on previous studies of cofactor-independent oxygenases and our results, we propose a radical-mediated catalytic mechanism for the cofactor-independent AlpJ-family oxygenases (Scheme 2). The catalytic cascade was initiated by

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• ). The reaction proceeded via the dehydrogenation of the alcohol, aldol condensation, and hydrogenation of α,β-unsaturated ketones. In 2019, Leitner and his group introduced an outstanding cascade BH approach for the synthesis of various substituted cycloalkanes by coupling diols and secondary alcohols

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• derivatives were isolated with good yields (Scheme 1). Instead, in the Senadi et al. approach, 1-(3-amino)-1H-indol-2-yl)-1-ketones were obtained through a Pd(0)-catalyzed cascade process consisting of isonitrile insertion as carbon monoxide surrogate and a C–H cross-coupling [13]. The reaction took place in

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• for the synthesis of functional materials via cross-coupling reactions. Next, we extended our investigation to 1-naphthol in this reaction, and found that the arylation of 1-naphthol was achieved selectively at the C-2 position. The cascade cyclization resulted in the corresponding products 3an and

• diaryliodonium salts in a cascade cyclization, the cyclization features a copper-catalyzed activation strategy involving the cleavage of the C–I bond and esterification. The resulting cascade of selective arylation/intramolecular cyclization facilitated the synthesis of 3,4-benzocoumarin derivatives. The

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• -tetrazole, which was successfully used in many asymmetric reactions via “enamine activation”, especially in asymmetric aldol reactions [20][21][22][23]. Moreover, compound IV was previously included in a study dealing with asymmetric cascade reactions (based on aldol reactions) of aldehydes with α-keto

Recent developments in the engineered biosynthesis of fungal meroterpenoids

• Zhiyang Quan and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

• cyclization process is initiated by the protonation of the epoxide, leading to the formation of a cation at C-7. A cascade of migrations then occurs to form the final backbone: H-6 migrates to the cation C-7, the methyl group at C-13 shifts to C-6, H-10 migrates to C-11, and finally, deprotonation of the